• The Korean Journal of Physiology and Pharmacology
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• v.2 no.5
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• pp.617-628
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• 1998

In order to understand the pathogenetic mechanism of adult respiratory distress syndrome (ARDS), the role of phospholipase A2 (PLA2) in association with oxidative stress was investigated in rats. $Interleukin-1{\alpha}\;(IL-1,\;50\;{\mu}g/rat)$ was used to induce acute lung injury by neutrophilic respiratory burst. Five hours after IL-1 insufflation into trachea, microvascular integrity was disrupted, and protein leakage into the alveolar lumen was followed. An infiltration of neutrophils was clearly observed after IL-1 treatment. It was the origin of the generation of oxygen radicals causing oxidative stress in the lung. IL-1 increased tumor necrosis factor (TNF) and cytokine-induced neutrophil chemoattractant (CINC) in the bronchoalveolar lavage fluid, but mepacrine, a PLA2 inhibitor, did not change the levels of these cytokines. Although IL-1 increased PLA2 activity time-dependently, mepacrine inhibited the activity almost completely. Activation of PLA2 elevated leukotriene C4 and B4 (LTC4 and LTB4), and 6-keto-prostaglandin $F2{\alpha}\;(6-keto-PGF2{\alpha})$ was consumed completely by respiratory burst induced by IL-1. Mepacrine did not alter these changes in the contents of lipid mediators. To estimate the functional changes of alveolar barrier during the oxidative stress, quantitative changes of pulmonary surfactant, activity of gamma glutamyltransferase (GGT), and ultrastructural changes were examined. IL-1 increased the level of phospholipid in the bronchoalveolar lavage (BAL) fluid, which seemed to be caused by abnormal, pathological release of lamellar bodies into the alveolar lumen. Mepacrine recovered the amount of surfactant up to control level. IL-1 decreased GGT activity, while mepacrine restored it. In ultrastructural study, when treated with IL-1, marked necroses of endothelial cells and type II pneumocytes were observed, while mepacrine inhibited these pathological changes. In histochemical electron microscopy, increased generation of oxidants was identified around neutrophils and in the cytoplasm of type II pneumocytes. Mepacrine reduced the generation of oxidants in the tissue produced by neutrophilic respiratory burst. In immunoelectron microscopic study, PLA2 was identified in the cytoplasm of the type II pneumocytes after IL-1 treatment, but mepacrine diminished PLA2 particles in the cytoplasm of the type II pneumocyte. Based on these experimental results, it is suggested that PLA2 plays a pivotal role in inducing acute lung injury mediated by IL-1 through the oxidative stress by neutrophils. By causing endothelial damage, functional changes of pulmonary surfactant and alveolar type I pneumocyte, oxidative stress disrupts microvascular integrity and alveolar barrier.

• Biomedical Science Letters
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• v.4 no.2
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• pp.87-101
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• 1998

There is considerable interests in the effect of regular, vigorous exercise, in particular weight training as a possible measure in improving myocardial function. The present investigation aimed to examine possible effect of a long-term weight training program on the heart in aging rats. Male rats aged 3-,10-, and 20-month-old were divided at random into a control (sedentary) and the exercise group. The training group was exercised for 5 days a week by 1 RM of ten times with weight training apparatus. This investigation examined the changes of the heart muscle relative to histological, ultrastructural, cytochemical, and stereological studies in rats. Quantity of lipofuscin pigments was clearly increased in the weight training group of 15-month-old rats, and mitochondrial degeneration, vacuolization, and interstitial proliferation were observed as well. In the weight training group of 25-month-old rats the frequency as separated intercalated discs, fraying myofibrils and hypercontraction band increased in number compared with the same 15-mon1h-old group. From the experimental result of glucose-6-phosphatase activity, the enzyme activities decreased in the weight training group of 15-month-old rats, and more decreased in the same 25-month-old group. In stereological study, both 15- and 25-month-old training groups, mitochondrial and myofibrilar volume densities significantly decreased, whereas interstitial volume density significantly increased. From the experimental results obtained in the present study, it is suggested that long-term weight training exercise do not cause any significantly qualitative and quantitative ultrastructural change of the heart muscle in the young. On the contrary, long-term weight training exercise stress may actually induce degenerative changes in the heart muscle in the old age.

• Applied Microscopy
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• v.27 no.2
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• pp.197-215
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• 1997

A morphologic study on the effect of butylated hydroxytoluene (BHT) on experimental hepatocarcinogenesis induced by 3'-methyl-4-dimethyl aminoazobenzene (3'-MeDAB) was investigated. A total of 110 Sprague-Dowley male rats weighting about 200 g each were used for the experiment, and divided into 4 groups; the 3'-MeDAB, BHT, 3'-MeDAB/BHT treated group, and the control group. Four to eight rats of each group were sacrified on the 4th, 8th, 14th and 16th experimental weeks, with continuous pelletized feeding containing 0.09% 3'-MeDAB and 0.5% BHT. The liver was examined by transmission and scanning electron microscopy. The results were as follows; Electron microscopically, the fine structure of the hepatocytes remained consistently abnormal up to 16 weeks after the 3'-MeDAB treatment. There was no significant difference in the groups observed earlier than in the ones observed later. Many subcellular changes were observed : nuclear change, decreased glycogen, mitochondrial abnormalities, disaggregated rough endoplasmic reticulum, marked proliferation of smooth endoplasmic reticulum, dilatation and distortion of bile canaliculi, increased lysosomes, apoptotic bodies, migration of bile ductule cell. In the BHT treated group, the ultrastructural changes of hepatocytes were not significant, except for the lipid droplets and proliferated smooth endoplasmic reticulum among hepatocytes depending on the experimental duration. The various subcellular changes of 3'-MeDAB/BHT treated groups were simillar to those of the 3'-MeDAB treated group, but the degree of changes in the 3'-MeDAB/ BHT treated group decreased compared with those of the 3'-MeDAB treated group. These results suggest that dietary butylated hydroxytoluene has a protective/inhibitory effect on the hepatocarcinogenesis induced by 3'-methyl-4-dimethyl -aminoazobenzene.

• Applied Microscopy
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• v.32 no.1
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• pp.45-55
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• 2002

The worm of Thelazia callipaeda Railliet et Henry, 1910 (The oriental eye worm) was frequently observed in the eyes of animal and human in Korea. But it did not clearly describe about the ultrastructural character on the sensory papillae and cuticular striation of the worm. This study was performed to investigate the ultrastructure and character on the cuticular surface of the worm that was extracted from the eyes of two patients in Korea University Medical Center, using the scanning electron microscopy. According to the mouth, 1/4, 1/2, 3/4 and tail portion of the worm, the size of cuticular striation on each portion was measured. The size of cuticular striation on the worm surface was $1.8{\mu}m$ in the mouth and tail portion, $4.0{\sim}4.5{\mu}m$ in the middle portion of the worm. On the scanning electron microscopy, the female worms were developed phasmids in the tail end and male worms were developed sensory papillae and external sexual organ on the tail end. The sensory papillae on the tail end were composed anterior ventral postcloacal papillae, middle ventral postcloacal papillae, subventral postcloacal papillae, and lateral papillae. According to the result in this study, it is considered that the character of the cuticular striation and the sensory papillae were able to accept as classifying key for the identification of species.

• Applied Microscopy
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• v.22 no.2
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• pp.15-29
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• 1992

The gallbladder is known to have the function of the storage and the concentration of the bile produced by the liver. This function is carried out by the removal of water and inorganic electrolytes. Extrahepatic cholestasis or the impairment of excretion of the bile leads to the distension and loss of the function of the gallbladder. The purpose of this study was to examine the ultrastructural characteristics of the normal gallbladder epithelial cells, and their structural changes induced by the ligation of common bile duct of the rabbit. Common bile duct ligation was performed under ether anesthesia. The rabbits were sacrificed on the 1st, 3rd, 5th, 7th and 14th day, respectively after operations. The tissue blocks of the gallbladder were fixed in 2.5% glutaraldehyde-1.5% paraformaldehyde prior to fixation in 1% osmium tetroxide, and embedded in the araldite mixture, and observed with JEM 100 CX-II electron microscope. The results were as follows: 1. The normal gallbladder epithelium of adult rabbit demonstrated two cell types, the ordinary epthelial cell and the dark cell. The dark cells have electron dense cytoplasm, and were found much infrequently, whereas ordinary epthelial cells were found quite numerous. 2. The ordinary epthelial cells of normal gallbladder were provided with the regular microvilli at the free surface and the images of pinocytotic activities in the apical cytoplasm, and exhibit highly convoluted lateral surfaces with elaborated microfolds. These figures of the cells suggest that they are resorptive in functional activity. 3. In the early stages (1st, 3rd, 5th day groups) following the ligation, the apical cytoplasm of some cells is protruding from the free surface and lost their microvilli. Numerous mucous granules filled in the apical and supranuclear cytoplasm compactly. 4. In the late stages (7th, 14th day groups) following the ligation, many light cells containing mumerous mucous granules are seen, between the ordinary epthelial cells. Mucous granules are fused each other, and are discharged into the lumen from the apical cytoplasm. The lateral membranes are straight or undulating without any interdigitations. From the above results, it was concluded that in the cholestasis induced by the common bile duct ligation, there is a tendency for the mucosal epithelium of the rabbit gallbladder to have secretory rather than an absorptive function.

• Applied Microscopy
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• v.29 no.3
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• pp.353-362
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• 1999

Di-(2-ethylhexyl) phthalate (DEHP) is a plasticize. known as one of endocrine disruptors. The present study was carried out to investigate the ultrastructural changes of prepubertal rat testis after oral administration of DEHP in dosages of 1 g/kg, 3 g/kg or 5g/kg in 0.5 ml of corn oil daily for a week. This study revealed the DEHP inhibited the development of seminiferous tubules and induced structural changes on various cell types of the rat testis. Leydig cells, Sertoli cells and the developing germ cells seemed to be impaired their differentiations in terms of the structural changes of cell organelles. The increase of heterochromatin in amount were common features in all 3 cell types. In addition, the Leydig cells were characterized by the increases in number and size of lysosomes and the scantiness of smooth endoplasmic reticulum. The Sertoli cells became irregular in nuclear envelope and the cytoplasm decreased, but the number of lysosomes and vacuoles seemed to be increased. There were some indications of necrosis of the germ cells, such as vacuolized nucleus and segregated nucleolus. These detrimental effects of DEHP on the rat testis were dose dependent and suppressed spermatogenesis decreasing developing germ cells in number and appearances. The effect of DEHP on ultrastructure of rat testis, as its known physiological functions, seems come from the decreased level of testosterone by Leydig cells, followed by the abnomalities of Sertoli cells and the germ cells.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.24 no.2
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• pp.403-410
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• 1994

The purpose of this study was to investigate the irradiation effects on the secretory granules of the rat submandibular gland acinar cell. For this study, Sprague-Dawley strain rats were irradiated to their neck region with the dose of 5Gy and l0Gy by 6MV X-radiation, and sacrificed on the experimental periods after irradiation. The authors observed the ultrastructural changes of the secretory granules of the rat submandibular gland acinar cell under a trasmission electron microscope. The results were as follows: In the transmission electron microscopic examination, secretory granules were blurred in limiting membrane on the 3hours groups after irradiation. And they showed decrease in number, irregularities in shape and distributional pattern, and inhomogeneous internal electron density on the Iday and 3days groups. After then, these changes were recovered in shape and distributional pattern on the 14days groups, and changes of internal electron density and limiting membrane were recovered on the 28days groups after irradiation. Among the intracellular organelles, rough endoplasmic reticulum was scattered, but golgi complex was not changed. And such pathologic changes were earlier and more prominent in 10Gy irradiated groups than in 5Gy irradiated groups.

• Applied Microscopy
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• v.29 no.3
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• pp.383-403
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• 1999

This study was performed to investigate the immunohistochemical and ultrastructural characterization of the choline acetyltransferase (ChAT)-immunoreactive nerve cells in the diagonal band of Broca of the rat basal forebrains, utilizing techniques of immunohistochemical and immunocytochemical microscopy. The ChAT-immunoreactivities were shown within neuronal cell bodies and processes by the light micoscope. According to cell shape and ratio of long axis vs short axis of cell body, the ChAT-immunoreaclive nerve cells in both vertical and horizontal limbs of the diagonal band of Broca were classified into 6 types. at the light microscopic level; round, oval, elongated, fusiform, triangular and polygonal types. As a result of the electron microscopic observation, the ChAT-immunoreactivated products appeared on the outer nuclear envelope, membranes of rough endoplasmic reticula (rER), free ribosomes and polysomes. Each cell type was subdivided into subtype I and II according to the several criteria such as volume of cell body, nuclear size relative to the cytoplasm, kinds and distribution of cell organelles and numbers and sorts of synapses. The subtype I of immnunoreactive nerve cells had large cell body and a small nucleus showing shallow indentations of nuclear evelope. In this subtype I with abundant cytoplasm, rER were well differentiated. Their long cisternae were parallelly ditributed and lamellated. One or two lamellar bodies and nematosomes were observed. The subtype II cell had small cell body and a large nucleus with deep indentations of nuclear envelope. In this subtype II with small cytoplasm, the rER were irregularly distributed and the lamellar body and nematosome were not found. A few axosomatic synapses in the subtype I and II were shown to be symmetric or asymmetric. The ratios of the symmetric synapse to the asymmetric one were investigated to be 1 : 2 and 1 : 4 in the subtype I and II, respectively. The axodendritic ones were almost asymmetric. But, the fusiform and triangular immunoreactive nerve cells were shown only to be subtype I. According to observations in this study, it is considered that the ultrastructural characterization in the 2 subtypes of each cell type may reflect the differences of the metabolic activities and projecting distances to the target cells.

• Journal of Oral Medicine and Pain
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• v.8 no.1
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• pp.33-41
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• 1983

The authors observed the ultrastructure of oral leukoplakia simplex of gingiva, buccal mucosa, tongue and alveolar ridge. For the purpose of clearly defining the lesions under investigation in this study, leukoplakias were cinsidered to be any white patches on the oral mucous membranes that could not be removed by rubbing and could not be classified clinically or microscopically as another diagnosable disease. The tissue to be examined were embedded in paraffin for light microscopic study. The tissue to be examined under the electronomicroscope were fixed in 2.5% glutaraldehyde in 0.1M cacodylate buffer and 1% osmic acid in 0.1M cacodylate buffer, dehydrated with guaded alchol, and treated with propylene oxide, and embedded in Epon.Ultrathin sections were obtained by LKB III ultrotome, stained with uranyl acetate/lead citrate, and examined with Corinth 500EM. The results were as follows : 1. Epithelium of leukoplakia consisted of stratum basale, stratum spinosum, stratum granulosum and stratum corneum. 2. There was hyperorthokerotosis or hyperparakeratosis. 3. Granular cells contained a lot number of membrane coating granule showing lamellar structure, clearing ot codensation, and a lot of keratohyaline granule varied in size. 4. An increased concentration of tonofilaments and an increased number of desmosomes were found in the stratum spinosum. 5. Basal lamina generally showed its continuity, but in some locatoins, its interreption and multiplication appeared.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.17 no.1
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• pp.27-49
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• 1987

Using ³H-proline as a radioactive tracer, the relationship between the ultrastructural differentiation and the site of protein synthesis has been investigated in developing red blood corpuscles. The general ultra-structure of erythropoietic cells in differentiation after 60 minutes of in vitro labeling has confirmed the results from previous investigations by Bessis, M., Thiery, J. and others. In dividing nuclei more than two-thirds of the labeling were present at the interface between heterochromatin and euchromatin. In less differentiated cells most of the grains in interphase cells was localized over the nucleus. As the cells continued to develope beyond a stage where cytoplasmic density was clearly increased over other cell lines in bone marrow, the majority of grains localized over the cytoplasmic area was decreased in more mature cells, as judged by the density of cytoplasm, and the structural changes in mitochondria, Golgi complex and polysomal configurations. These results show; 1) that the cytoplasm of erythroblast series does not change under in vitro conditions employed in the study; 2) that protein synthesis in the nucleus occurs largely at the interface between euchromatin and heterochromatin in active nuclei; and 3) that cytoplasmic synthesis of proteins continues to take place well into the normoblast stage solong as the physically visible polysomes are present in maturing red blood corpuscles.